1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
|
/* Low-level debug register code for GNU/Linux x86 (i386 and x86-64).
Copyright (C) 1999-2023 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "gdbsupport/common-defs.h"
#include "nat/gdb_ptrace.h"
#include <sys/user.h>
#include "target/waitstatus.h"
#include "nat/x86-linux.h"
#include "nat/x86-dregs.h"
#include "nat/x86-linux-dregs.h"
/* Return the offset of REGNUM in the u_debugreg field of struct
user. */
static int
u_debugreg_offset (int regnum)
{
return (offsetof (struct user, u_debugreg)
+ sizeof (((struct user *) 0)->u_debugreg[0]) * regnum);
}
/* Get debug register REGNUM value from the LWP specified by PTID. */
static unsigned long
x86_linux_dr_get (ptid_t ptid, int regnum)
{
int tid;
unsigned long value;
gdb_assert (ptid.lwp_p ());
tid = ptid.lwp ();
errno = 0;
value = ptrace (PTRACE_PEEKUSER, tid, u_debugreg_offset (regnum), 0);
if (errno != 0)
perror_with_name (_("Couldn't read debug register"));
return value;
}
/* Set debug register REGNUM to VALUE in the LWP specified by PTID. */
static void
x86_linux_dr_set (ptid_t ptid, int regnum, unsigned long value)
{
int tid;
gdb_assert (ptid.lwp_p ());
tid = ptid.lwp ();
errno = 0;
ptrace (PTRACE_POKEUSER, tid, u_debugreg_offset (regnum), value);
if (errno != 0)
perror_with_name (_("Couldn't write debug register"));
}
/* Callback for iterate_over_lwps. Mark that our local mirror of
LWP's debug registers has been changed, and cause LWP to stop if
it isn't already. Values are written from our local mirror to
the actual debug registers immediately prior to LWP resuming. */
static int
update_debug_registers_callback (struct lwp_info *lwp)
{
lwp_set_debug_registers_changed (lwp, 1);
if (!lwp_is_stopped (lwp))
linux_stop_lwp (lwp);
/* Continue the iteration. */
return 0;
}
/* See nat/x86-linux-dregs.h. */
CORE_ADDR
x86_linux_dr_get_addr (int regnum)
{
gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
return x86_linux_dr_get (current_lwp_ptid (), regnum);
}
/* See nat/x86-linux-dregs.h. */
void
x86_linux_dr_set_addr (int regnum, CORE_ADDR addr)
{
ptid_t pid_ptid = ptid_t (current_lwp_ptid ().pid ());
gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
iterate_over_lwps (pid_ptid, update_debug_registers_callback);
}
/* See nat/x86-linux-dregs.h. */
unsigned long
x86_linux_dr_get_control (void)
{
return x86_linux_dr_get (current_lwp_ptid (), DR_CONTROL);
}
/* See nat/x86-linux-dregs.h. */
void
x86_linux_dr_set_control (unsigned long control)
{
ptid_t pid_ptid = ptid_t (current_lwp_ptid ().pid ());
iterate_over_lwps (pid_ptid, update_debug_registers_callback);
}
/* See nat/x86-linux-dregs.h. */
unsigned long
x86_linux_dr_get_status (void)
{
return x86_linux_dr_get (current_lwp_ptid (), DR_STATUS);
}
/* See nat/x86-linux-dregs.h. */
void
x86_linux_update_debug_registers (struct lwp_info *lwp)
{
ptid_t ptid = ptid_of_lwp (lwp);
int clear_status = 0;
gdb_assert (lwp_is_stopped (lwp));
if (lwp_debug_registers_changed (lwp))
{
struct x86_debug_reg_state *state
= x86_debug_reg_state (ptid.pid ());
int i;
/* Prior to Linux kernel 2.6.33 commit
72f674d203cd230426437cdcf7dd6f681dad8b0d, setting DR0-3 to
a value that did not match what was enabled in DR_CONTROL
resulted in EINVAL. To avoid this we zero DR_CONTROL before
writing address registers, only writing DR_CONTROL's actual
value once all the addresses are in place. */
x86_linux_dr_set (ptid, DR_CONTROL, 0);
ALL_DEBUG_ADDRESS_REGISTERS (i)
if (state->dr_ref_count[i] > 0)
{
x86_linux_dr_set (ptid, i, state->dr_mirror[i]);
/* If we're setting a watchpoint, any change the inferior
has made to its debug registers needs to be discarded
to avoid x86_stopped_data_address getting confused. */
clear_status = 1;
}
/* If DR_CONTROL is supposed to be zero then it's already set. */
if (state->dr_control_mirror != 0)
x86_linux_dr_set (ptid, DR_CONTROL, state->dr_control_mirror);
lwp_set_debug_registers_changed (lwp, 0);
}
if (clear_status
|| lwp_stop_reason (lwp) == TARGET_STOPPED_BY_WATCHPOINT)
x86_linux_dr_set (ptid, DR_STATUS, 0);
}
|
